This invention relates generally to mattress foundation structures and more particularly to a box spring assembly of a type which utilizes non-coil springs. Box spring assemblies of this general type have been know since 1964, the first such spring assembly being disclosed in U.S. Pat. No. 3,286,281. Subsequently issued patents disclosing the same general type of box spring assembly are: U.S. Pat. Nos. 3,487,480; 3,506,987; 3,574,240; 3,574,241; 3,665,529; 3,680,157; 3,755,833; 3,824,639; 3,852,838; and 4,131,961. Box spring assemblies of the general type shown in the above list of patents, all of which are assigned to the assignee of this application, are advantageous with respect to the conventional box spring assemblies using coil springs because they provide a desired stiffer foundation for the mattress and contain a reduced amount of wire. These box spring assemblies are also advantageous from the standpoints of prolonged service life, ease of assembly, and cost of manufacture.
Additional box spring assemblies of this general type are shown in U.S. Pat. Nos. 3,596,299; 3,722,013; 3,825,960; 3,833,948; 3,835,485; 3,869,740; 3,990,121; and 4,000,531.
The present invention provides a box spring assembly which utilizes a basic wire grid in combination with a wire spring assemblage in a manner that enables the use of fewer springs, assures the desired uniform support for a mattress, and simplifies the assembly of the grid with the spring assemblage.
It is an object of the present invention, therefore, to provide an improved box spring assembly in which a basic wire grid is combined with a wire spring assemblage that includes individual springs arranged to achieve a desired degree of mattress support.